The present invention relates to a fixing structure of sashes of a motor vehicle door, and more particularly, to a fixing structure of a main sash in an outer frame portion of a window and a middle sash provided between fixed and movable panes of glass of a motor vehicle door having the windowpane divided into the fixed and the movable panes.
Japanese Utility Model Laid-Open Pub. No. 59-120624 discloses a door window device for a motor vehicle, in which the windowpane is divided into a fixed upper pane and a movable lower pane. The upper pane has a concave edge forming member along the lower edge thereof, while the lower pane has a convex edge forming member along the upper edge thereof. The concave and convex members combinedly form a middle door sash when the movable lower pane is elevated against the fixed upper pane.
On the other hand, in order to secure the rigidity of an opening part of a window shoulder of a conventional motor vehicle door, the only method available is to strengthen a reinforcing member longitudinally attached along the window shoulder to the outer panel of the door and to the inner panel thereof. Particularly, the longer the door in the front-to-rear direction, the more difficult it becomes to secure the rigidity of the opening part of the window shoulder.
In order to improve the rigidity of the window shoulder, there have been devised a structure comprising a main door sash defining the upper and front contour of the door, a middle door sash disposed below and along the main door sash, and coupling reinforcing means securely coupling the leading ends of the two sashes, the coupling reinforcing means being fixed to longitudinal reinforcing members extending along the window shoulder of the door.